This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A171007 #7 Dec 09 2018 12:07:19 %S A171007 2,1,4,6,3,7,8,60,9,11,14,17,61,16,22,25,30,26,28,34,49,37,200,36,38, %T A171007 39,42,59,51,54,56,62,68,2000,63,67,80,69,70,72,73,82,90,600,81,83,91, %U A171007 601,84,92,97,103,201,104,106,107,112,113,120,126,130,202,131 %N A171007 Sequence S constructed with the property that the next term is the smallest integer not yet present in S such that the sum of the a(n) first digits of S is a prime. %C A171007 Further work is needed to establish that the sequence is well-defined and that this is the correct beginning. %K A171007 nonn,base %O A171007 1,1 %A A171007 _N. J. A. Sloane_, Sep 03 2010, based on discussions in the Sequence Fans Mailing List, started by Eric Angelini, with contributions from _M. F. Hasler_ and _D. S. McNeil_